Analyzing the Effect of Cantilever Dimensions on the Dynamic of AFM Higher Modes in Air Environment

Nowadays, AFM has a crucial role in topography and property estimation of biological samples. One way to increase contrast of images is exciting higher modes or exciting several modes simultaneously (Multifrequency AFM). In This paper, dynamic behavior of atomic force microscopeʹs higher modes has been studied. Cantilever of AFM has been modeled by Timoshenko beam which the effects of rotational inertia and shear deformation are taken into consideration. Non-linear interaction forces between sample and tip has been considered in air media. Then effect of cantileverʹs dimensions on the frequency and amplitude of higher modes of dAFM (dynamic atomic force microscope) in air has been analyzed. Results provide good guide line for AFM users that choose the best dimensions of cantilever by considering the range of frequency and amplitude that can be acceptable for nth mode of atomic force microscope as there is limitation for resonant frequencies and amplitude which is directly dependent to samplesʹ softness and detectorʹs readable range.